Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Structure of the glacial thermocline at Little Bahama Bank

Abstract

Within the thermocline of the western North Atlantic, bathymetric gradients of hydrographic properties are controlled by the lateral movement of water along isopycnal surfaces1–4. This movement is driven by air–sea interaction processes :Ekman pumping and sur-face heat (buoyancy) flux. By affecting the intensity of these processes, glacial7ndash;interglacial climatic change should also affect the bathymetric gradients of properties within the thermocline. Benthic foraminifera live on carbonate bank margins that intersect the thermocline. These foraminifera record the hydrographic gradients in their isotopic shell chemistry, providing the means to reconstruct changes in thermocline structure and circulation. We have measured the δ18O compositions of a near-surface planktonic foraminifer, Globigerinoides ruber, and a shallow-water benthic foraminifer, Cibicidoides floridanus, in a core recovered from Little Bahama Bank. Cibicidoides floridanus exhibits a glacial–inter-glacial range in δ18O that is 0.5% less than G. ruber's, because individuals of this species lived and calcified ~110m shallower on the thermocline ~ 18,000 yr ago. After glacio-eustatic changes in thermocline position are accommodated, we estimate that temperature at 540 m palaeodepth cooled by ~ 2 ° C. Globigerionoides ruber δ18O values suggest that surface water temperature at this location also cooled by ~2 °C. This uniform cooling of the upper 600 m of the water column is consistent with the observation that surface water where isopycnals outcrop was ~2 °C cooler during the glacial maximum5–8.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others

References

  1. 1. Islen, C. O'D. Trans. Am. geophys. Un. 20, 414–417 (1939). 2. Jenkins, W. J. J. mar. Res. 38, 533–569 (1980). 3. Luyten, J., Pedlosky, J. & Stommel, H. /. Phys. Oceanogr. 13, 292–309 (1983). 4. Luyten, J. & Stommel, H. J. /. phys. Oceanogr. 16, 1551–1560 (1986). 5. CLIMAP Project Members Science 191, 1131–1137 (1976). 6. Mclntyre, A. et al. Geol. Soc. Am. Mem. 145, 43–76 (1976). 7. CLIMAP Project Members Geol. Soc. Am. Map Chart Ser. 36 (1981). 8. Manabe, S. & Broccoli A. J. /. geophys. Res. 90, 2167–2190 (1985). 9. Burns, S. J. M. S. thesis Univ. North Carolina (1983). 10. Burns, S. J. & Neumann, A. C. Marine Geology (Submitted). 11. Poag, C. W. Ecologic Atlas of Benthic Foraminifera of the Gulf of Mexico (Hutchison Ross, Stroudsburg, 1981). 12. van Morkhoven, F. P. C. M., Berggren, W. A. & Edwards, A. S. Cenozoic Cosmopolitan Deep–water Benthic Foraminifera (Elf Aquitaine, Pau, 1986). 13. Curry, W. B. & Lohmann, G. P. Quat. Res. 18, 218–235 (1982). 14. Shackleton, N. J., Imbrie, J. & Hall, M. A. Earth planet. Sci. Lett. 65, 233–244 (1983). 15. Shackleton, N. J. & Pisias, N. G. Geophys. Monog. 32, 303–317 (1985). 16. Keigwin, L. D., Corliss, B. H., Druffel, E. R. M. & Laine, E. P. Quat. Res. 22,383–386 (1984). 17. Berger, W. H., Killingley, J. S. & Vincent, E. Nature 314, 156–158 (1985). 18. Duplessy, J. C., Arnold, M., Maurice, P., Bard, E., Duprat, J. & Moyes, J. Nature 320, 350–352 (1986). 19. Olson, D. B., Schott, F. A., Zantopp, R. J. & Leaman, K. D. J. phys. Oceanogr. 14,1470–1487 (1984). 20. Epstein, S. & Mayeda, T. Geochim. cosmochim. Acta 4, 213–224 (1953). 21. Broecker, W. S. Quat. Res. 26, 121–134 (1986). 22. Epstein, S., Buchsbaum, R., Lowenstam, H. & Urey, H. C. Bull. geol. Soc. Am. 64,1315–1326 (1953). 23. Craig, H. in Proc. Spoleto Conf. on Stable Isotopes in Oceanographic Studies and Paleo–temperatures Vol. 3 (ed. Tongiorgi, E.) (1965). 24. Emiliani, C. Am. J. Sci. 252, 149–158 (1954). 25. Jones, J. I. Micropaleont. 13, 489–501 (1967). 26. Lidz, B., Kehm, A. & Miller, H. Nature 217, 245–247 (1968). 27. Berger, W. H. Deep Sea Res. 16, 1–24 (1969). 28. Shackleton, N. J. & Vincent, E. Mar. Micropaleont. 3, 1–13 (1978). 29. Fairbanks, R. G., Wiebe, P. H. & Be, A. W. H. Science 207, 61–63 (1980). 30. Curry, W. B. & Matthews, R. K. Mar. Micropaleont. 6, 327–337 (1981). 31. Deuser, W. G. Deep Sea Res. (in the press). 32. Deuser, W. G. Palaeogeogr. Palaeoclimatol. Palaeoecol. 33, 103–127 (1981). 33. Shackleton, N. J. & Opdyke, N. D. Quat. Res. 3, 39–55 (1973). 34. Shackleton, N. J. in Fate of Fossil Fuel CO2 (eds Andersen, N. R. & Malahoff, A.) 401–427 (Plenum, New York, 1977). 35. Woodruff, F., Savin, S. M. & Douglas, R. G. Mar. Micropaleont. 5, 3–11 (1980). 36. Belanger, P. E., Curry, W. B. & Matthews, R. K. Palaeogeogr. Palaeoclimatol. Palaeoecol. 33, 205–220 (1981). 37. Graham, D. W., Corliss, B. H., Bender, M. L. & Keigwin, L. D. Mar. Micropaleont. 6, 483–497 (1981). 38. Chappell, J. & Shackleton, N. J. Nature 324, 137–140 (1986). 39. Fairbanks, R. G. & Matthews, R. K. Quat. Res. 10, 181–196 (1978). 40. Hunter, G. E. M. S. thesis Miami Univ. (1984). 41. Boardman, M. R., Neumann, A. C., Baker, P. A., Dulin, L. A., Kenter, R. J., Hunter, G. E. & Kiefer, K. B. Geology 14, 28–31 (1986). 42. Luyteen, J., Pedlosky, J. & Stommel, H. Clim. Change 5, 183–191 (1983). 43. Hays, J. D. & Perruzza, A. Quat. Res. 2, 355–362 (1972). 44. Parkin, D. W. & Shackleton, N. J. Nature 245, 455–457 (1973). 45. Parkin, D. W. Proc. R. Soc. Lond. A 337, 73–100 (1974). 46. Parkin, D. W. & Padgham, R. C. Proc. R. Soc. Lond. A 346, 245–260 (1975). 47. Gates, W. L. Science 191, 1138–1144 (1976). 48. Gardner, J. V. & Hays, J. D. Geol. Soc. Am. Mem. 145, 221–246 (1976). 49. Kolla, V., Biscaye, P. E. & Hanley, A. Quat. Res. 11, 261–277 (1979). 50. Kutzbach, J. E. & Guetter, P. J. /. atmos. Sci. 43, 1726–1759 (1986). 51. Ruddiman, W. F. & Mclntyre, A. Quat. Res. 3, 117–130 (1973).

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Slowey, N., Curry, W. Structure of the glacial thermocline at Little Bahama Bank. Nature 328, 54–58 (1987). https://doi.org/10.1038/328054a0

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/328054a0

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing